Base threading method and apparatus



Jan. 2, 1951 v, BRUNNER ETAL 2,536,677

BASE THREADING METHOD AND APPARATUS Filed Aug. 31, 1944 2 Sheets-Sheet 1 TATE. Q

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G. V. BRUNNER EI'AL BASE THREADING METHOD AND APPARATUS Jan. 2, 1951 Filed Au 31, 1944 Patented Jan. 2, 1951 BASE THREADING METHOD AND APPARATUS George V. Brunner and John J. Gresko, Em-

porium, Pa., assignors to Sylvania Electric Products Inc., Emporium, Pa., a corporationof Massachusetts Application August 31, 1944, Serial No. 552,180

7 Claims. (Cl. 29-2519) This invention relates tov methods and appa ratus for assembling groups of wires such as those of. electric cables into plugs, and more particularly to methods of inserting the lead-in wires of a discharge tube into the pins of the associated hollow-pronged base of known constructions.

The threading of the lead-in wires into the pins of radio tubes,-cathode-ray tubes and other discharge tubes has heretofore been effected by hand. That procedure is not too diflicult to follow when the side walls ofthe tube base are shorter than or about equal to the diameter of the disc-shaped bottom plate of the base, in which the contact pins are fastened; or as long as the number of pins and corresponding tube lead-ins is reasonably small. It requires however, in all cases, skill and causes eye strain. Any error in the coordination of base pin andtube lead-in will make an otherwise good tube inoperative in the standardized socket provided for each type of tube.

A particularly undesirable condition exists in the case of certain types of cathode-raytubes in which the number of lead-in wires is large, as in cathode-ray tubes with complicated electron guns, several sets of electrostatic deflection plates and large potential differences exist between the neck of the cathode-ray tube and base, and in which the cylindrical part of the base must be long e. g., four inches, as compared to a two inch .diameter radio tube neck. As a result it becomes very difficult to thread the soft or easily bendable leadin wires of these tubes into the pins at the bottom of the base.

It is therefore, an object of the invention to provide means for quickly and accurately threading a large number of tube lead-in wires int the hollow contact pins of a tube base or the like. As a result both hands of a basing operator are freed for threading simultaneously two lead-1n wires at a time into the correct channels in the corresponding base pins.

Another object of the invention relates to the use of auxiliary rigid hollow needles, which serve as rigid guiding means for threading flexible or easily bendable lead-in wires through the narrow channels of the base pins. By this means it is possible to guide simultaneously all the lead-in wires of a discharge tube through the corresponding channels in the base pins. Likewise, there are obtained perfectlystraight lead-in wire portions between the tube header and the corresponding base pins inside the base.

A feature of the invention relates to a staggered disposition of the exposed threading ends of auxtroduction of lead-in wires is materially fled.

Another feature of the means for removing basing cement from the interior of the auxiliary hollow threading needles after each basing cycle, whereby 1 an undesired. accumulation and hardening of this basing cement inside the auxiliary threading tube is prevented. Other objects and features of the invention will be discussed as the description. proceeds, which will be given in connection with the drawing, in which,

Fig 1 is a generalized view showing the relation between the guides, the tube base and the tube header in practicing the invention.

Fig. 2 is a sectional viewof Fig. 1 along the line 22 thereof.

Fig. 3 is a sectional view of Fig. 1 along the vline 3-3.

Fig. 4 is a view partly sectional, showing one step in the threading operation.

Fig. 5 is a partial sectional view showing another step in the threading operation.

Referring to the drawing, numeral I indicates a cylindrical cup-shapedbase in vertical section, consisting of cylindrical wall 2, base plate 3, and downwardly depending center stud 4. This base may be molded of a single piece of plastic, or made partly of metal and partly of insulating material. In the base plate 3iare arranged a number of holes 5 preferably in circular array and in which are held for example by eyelets i, the pins or plug-in contact prongs I. If desired, radial ribs 8 may be disposed above and between the holes 5 forpreventing contact between the various lead-in wires 9 to be threaded through pins 1. The various lead-in wires 9 depend from the stem or header. ll) of an electron discharge tube, having a tipped-oil exhaust tubulation I I.

A fixture l2 consisting of eight hollow threading needles I3 held by plate I! is indicated in Figs. 4 and 5. These hollow needles are equally spaced around a circle as shown in Figs. 2 and 3.,

This fixture is shown in Fig. I mounted on an inclined block I, which is rigidly attached to a table IS.

The threading needles are fastened by eyelets the hollow threading needles l3, inserting them iliary hollow needles, whereby the consecutive in- 66 into'the bores I! of the base plus, in a positicn simpliinvention relates A A as shown in Fig. 4. The tips I! oi needles I! are cut oil at an angle, thus providing an openins larger than the inner diameter of the threading needles, to expedite insertion of the lead-in wires I. Preferably, the needles are of successively greater length as indicated in Figs. 4 and 5. This unequal or stepped length is provided so as to correspond to the respective lead-in wires which are likewise of different lengths whereby confusion of lead-ins is prevented.

In this arrangement, the tube may be held in one hand by the operator, who uses the other hand for guiding the lead-in wires into the open ends of the threading needles. Preferably, the tube is supported at a convenient distance from and centered with device i2 by a suitable support 2| (Fig. 1), whereby both hands of the operator are free for threading. After all the leads are inserted in their corresponding threading needles, the base 2 is moved upward and slipped over the bottom part 2| of the tube. During this motion, the lead wires 9 remain stationary inside the threading needles i2, thus providing the flexible lead-in wires with a rigid shell of uniform diameter during their passage through the channels of the base pin, in contrast to the hollows through pin 1 that are necked in at their lower ends.

The base threading fixture I2 is formed as a perforated socket 22, into which the base pins 1 of tube base 2 can be inserted. The plate I1 is attached to a piston member 23 which can be moved up and down within fixture i2 by means of an operating lever 24, which may be controlled by a pedal 25.

Arranged to pass inside the needles I: are needle plungers 26, which are attached at their lower ends to a stationary botto'm plate 21 of fixture 'i2. These needle plungers are provided for pushing out any of the cement from the usual cement ring 28 which may have entered the tubular needles 13 during their upward motion.

In order to thread the leads into the base pins, the operator proceeds as follows. The needles II are slipped down all the way over the plungers 26 (Fig. leaving free the female openings 2! on top of socket fixture l2, it being understood that plate I1 is in itslowermost position. Into these openings 29 are now inserted the base pins I, in the ordinary way a tube baseis plugged into any plug-in socket. By manipulating pedal 25, member 23 is pushed upward all the way in socket fixture i2, bringing' up with it all the needles l3 simultaneously through the holes of the corre-. sponding base pins. In the positionas shown in Fig. 4, the upper ends of the threading needles are extended over and above the upper rim 30 ofbase2. a

In the meantime, the same or another operator has placed tube 2| in aligned positionwlth the fixture l2,.by means of support 22. The loose fiexibl-e tube lead-in wires 9 are properly separated and straightened andthe position of the tube in support is preferably so .chosen that the lead-ins are easily insertable into the threading needles... The operator has now both handsfree to introduce the tube lead-ins 9 into the obliquely cut top ends 19 of needles i3. Preferably, the height of these needle ends is so chosen that it is just slightly lower than .the eyes of the operator, for convenient observation in threading.

vAfter threading, the.base.2 ismanually moved upward toward the tube neck as far as it vWill go, thus guiding the soft lead-in wires, externally supportedv by the rigid threading needles, easily and automatically into the holes lathe base pins and through the necked-down ends of the pins.

The threading needles are now pulled down into the socket under control of lever 24, and the base and tube assembly is ready for the baking oven. The lead-ins are cut off and soldered as usual after baking.

During their upward motion through the base 2, the hollow needles II have passed near thesoft cement ring 28, and it frequently happens that some of this cement mayenter the needles. This does not interfere directly with the proper functioning of the threading device, because the cementis soft before baking. If the process is repeated however. too much cement might accumulate inside the hollow needles, and the cement might harden by drying out, and plug up the inside of the threading needles.

In order to prevent this undesirable accumulation of cement, the plungers 22 are provided.-

Before inserting the next tube base into the socket fixture l2, the needles II are pulled down to their lowest position by means of member 22. In this lowest position of the needles II, the upper ends of plungers 26 are just a little higher than the open ends I! of needles i3, and any cement or other undesirable material that may haveentered needles l2 during the preceding threading cycle, is pushed out of the needles by the plungers 26 during the lowering of the needles.

While the invention has been described in con-- nection with a cathode-ray tube, and basing devices with eight pins have been shown in the drawing, it is obvious that the principle of base threading may be applied to any type of electrondischarge tube, and to bases with any number of lead-ins. Another application of the described thread'ng methods, which falls within the scope of our invention is the threading of a plurality of lead terminals of an electric cable or connector into the prongs of a plug-in base.

What is claimed is: 1. In a device of the character described, a plug-in receptacle adapted to receive a hollowpron ged tube base, a plurality of reciprocal hollow tubular guides within said receptacle and arranged to be moved so that they project through the receptacle openings into telescopic relation with the prongs interiorly thereof, and means to move said guides so that they project beyond the base into easy threading relation with the corresponding set of lead-in wires.

2. A device acoording'to claim l,'in which said guides are supported on a common vertically movable plate.

'3. A device according to claim 1 in which said guides are provided with individual rods afllxed to the bottom of said receptacle and adapted to telescope" within the guides when the guides are in their non-raised position.

4. A socket fixture for usein'threading leadinwires through the holes of the contact prongs of a tube base comprising a top plate provided with holes for receiving the-contact prongs of a. tube'base, side walls, a bottom wall and a plate movable up and down between top and bottom wall of the socket fixture, an assembly of hollow to the bottom plate and arranged coaxial with and inside the threading needles.

5. A socket fixture according to claim 4 in which the means for moving the movable plate up and down consists of a piston rod attached to the center of the moving plate and passing through a hole in the center of said bottom plate.

6. A socket fixture according to claim 4 in which the holes in the top plate are arranged on a circle, and the side walls of the socket fixture consist of a cylindrical shell.

7. A device according to claim 1, in which said guides are supported at one end on a. common vertically movable plate and said guides vary in length so that their other ends, remote from said plate, are in successive stepped relation with regard to said plate.

GEORGE V. BRUNNER. JOHN J. GRESKO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,612,537 Schroeder Dec. 28, 1926 1,817,746 Gooskens Aug. 1, 1931 2,262,901 Murphy Nov. 18, 1941 15 2,349,956 Gliss et al May 30, 19% 

